2009 Mercedes Benz GL320

The long days on the road are coming to a close, thankfully.   Our drive from Columbia MO to Independence IA (300 miles) ended with a boom, literally.   Less than 30 minutes after we arrived at the small city-run RV park here, a wave of intense thunderstorms passed through and terrorized us for a couple of hours.   The clouds above were forming counter-clockwise swirls — a very bad sign — and the winds were strong enough to rock the trailer even with the stabilizers down.   As always, when caught in bad weather, we began looking for an emergency exit, which in this case would have been a nearby brick shower house.

Fortunately, the storms passed over us without causing any damage, and eventually left us with a gorgeous red and blue sunset, and fewer dead bugs plastered to the exterior skin of the Airstream.

dsc_0014.jpgI am still talking to the manufacturer about the hitch problem we encountered recently, but since I’m getting “outed” left and right by my friends, I will go ahead and start acknowledging the new tow vehicle.   It’s a 2009 Mercedes Benz GL320 with “Bluetec” engine.   We chose this because it is a diesel 7-passenger SUV which meets our needs.   We expect to use it for many years of towing.   Sadly, with American and Japanese manufacturers pulling back on their promised diesel vehicles, the only diesel SUVs available new are coming out of Europe.   VW, BMW, Audi, and MB all offer them today, while Nissan, Toyota, Chrysler, GM, and Honda have all announced light diesel programs and then canceled them.

I know this will kick off a firestorm of questions and controversy, because I’ve chosen a non-traditional tow vehicle.   I’ll try to answer the FAQs here:

Fuel consumption:   So far, with the engine still breaking in, we are getting 14.0 MPG towing at 60 MPH, flat to moderately rolling terrain, no wind.   Going to 65 MPH costs us 1 MPG. I am told that the economy will improve as the engine breaks in.   Still, that’s a solid 30% increase over the Armada.

Loading:   Yes, we are under the vehicle weight ratings.   That includes Gross Vehicle Weight Rating (GVWR), and Gross Axle Weight Ratings (GAWR).   The factory hitch is rated to 7500 lbs and 600 lbs of tongue, but we’ve substantially reinforced it, as readers of this blog know.   I regard the factory hitch as inadequate for even the rated 600 lbs of tongue weight, so beware.

Performance: The ride and handling are excellent, once hitched up properly.   The interior is as quiet as you’d expect.   Power is excellent, thanks to the diesel engine that puts out 398 ft-lbs of torque.   It’s unbelievably quiet when running, to the point that many people don’t know it is a diesel.   The 7-speed automatic keeps the engine in the ideal power band all the time.   I think that once other manufacturers get their acts together, engine/transmission combinations like this will be the future of recreational towing.

What I like compared to the Armada:   Better fuel economy (22/28 MPG not towing), much nicer to drive especially when not towing, better towing handling at highway speed, high ground clearance when off-roading, extensive safety and security features, cheaper insurance, less propensity to roll over, much more powerful air conditioning, slightly more torque, diesel reliability and durability, 7-speed transmission, less frequent oil changes, longer cruising range, full-time AWD.

What I don’t like compared to the Armada:   Expensive to buy, slightly more expensive to maintain, no spare tire, less interior space, slightly less carrying capacity, too much tricky electronics, smaller sideview mirrors, limited third-row access, no aftermarket hitches, no low range, fewer service centers, expensive tires.

Recommendation?:   Most people travel with a ton of “stuff.”   Most people never weigh their rig, either.   For best value, largest cargo area, and less concern about overloading, go with a pickup truck.   Seriously.   For most people, that’s the right choice.   Many of the SUVs require you to think carefully about what you carry, to avoid overloading the rear axle.

Also, Mercedes is not particularly oriented to towing.   The 2009 GL’s have a driver’s side knee airbag, which makes placement of the brake controller more challenging.   The 2009 models also have a urea tank (part of the “clean diesel” exhaust system) where the spare normally goes, so there’s no spare tire.   (It uses run-flat tires, and I carry a tire plug kit, but there is no substitute for a spare.   This is the major flaw of the design.)

The hitch design is inadequate, as I’ve already mentioned. There are no aftermarket hitches that fit this car, so you must buy the factory hitch — and even when you do get that option, you have to buy some wiring for the brake controller and there’s an additional charge to reprogram one of the computers so that the car will send signals to the brake controller.   For me the icing on the cake was that the computer is so “smart” it won’t recognize a trailer with LED lights, so you have to go through some hoops to fix that issue as well.

So with all those issues and limitations, you might wonder why I bothered with it.   Why not buy a 2009 Dodge RAM 2500 4×4 with Cummins diesel with Megacab, for $56k?   Well, some people like driving trucks, and some people don’t.     As part of this exercise I have talked to quite a number of people who are currently towing with Mercedes (mostly the less expensive and smaller ML-class), and they all love them.   I’ve also talked to many people who tow with big pickups and love them.   To each their own, I say.   Be safe, and have fun.

I’ll report further on the performance of the Mercedes as we accumulate miles.   The real proof of its appropriateness for the task will come only after many miles and (at least) several years of towing.

Today we are going to check out a Frank Lloyd Wright house here in Independence, and then scoot up to Madison.   There will be no escape from the heat, however.     The “Airstream effect” has already begun.   Whenever hundreds of Airstreams gather for the International Rally, the local area always experiences record high temperatures.   The poor people of Madison WI have no idea what is coming, I fear.   If we don’t hit 100 degrees during the rally week, it will be the first time in many years.


  1. abe says

    Thank you for telling us what you were driving. I had narrowed it down to the Audi or MB and I just had looked up the Audi’s tow rating 6600# and knew that I was close… but now back to “work” thanks for the daily posts!!

  2. Barry says

    Excellent post!

    Glad to know you are reasonably happy with the new vehicle. I never owned a diesel before my Chevy, and now think America should be a one fuel nation, with diesel being that fuel. I know there are problems in cold weather with the older ones, but most have been solved.

    Have you gotten a recall notice on your Airstream? I haven’t gotten one, (my dealer went bankrupt) but someone sent me a copy of the notice. The NTSB wants a reflector put on the back. It concerns only the ones with LED tailights. Just wondering.

  3. says

    glad you fessed up!….but even though it is a car/SUV I wouldn’t associate with you, I know you made your decision based on safety for your lifestyle..and I know you also made the decision based on enormous amounts of research. Travel safely! Regards to E&E.

  4. says

    Nice specs for a V-6. You’ve got my 5.7 liter Hemi beat by about 50 foot-pounds of torque and I tow less. I’d certainly like to consider a small diesel in an SUV configuration and can see that the nice ones will be coming from my favorite German manufacturers. However, if I’m not mistaken, all seem to be unibody chassis rather than truck chassis that are arguably better suited to towing. I’m sure that you will tell us if some of the welds pop or if the body starts contorting in strange ways. Best of luck with the MB.

  5. says

    I wonder if you considered the VW Touareg TDI, the 3-liter, V-6 version. Similar specs to the MB, with just a bit more torque, less weight and price, and more towing capacity. Not as sexy as the MB though.

  6. Karen Britting says

    Rich, gosh I’d love to tease you if I could, but I can’t on this one – German cars rock! (imho). Enjoy! Can’t wait to take it for a test drive when you get here.


  7. says

    Mike, good questions. (1) It is a unibody, but an extremely strong one, with high-strength steel and heavy frame elements built into it. The myth that unibodies can’t tow needs to be exploded. They’re not all the same. I’ll certainly be on the lookout for unusual tire wear, or other symptoms, but this body is probably stronger than many body-on-frame trucks overall.

    (2) I did consider the new VW Touareg2 TDI V-6, but it wasn’t available until later in June. Also, it’s a 5-passenger vehicle with 10″ less wheelbase. We needed something larger. But at a base of $42k and similar power specs to the MB, it’s a worthy vehicle for people with less to carry and a shorter trailer.

    (3) The urea (“AdBlue”) thing is less of an issue than it might seem. The car gives a 1,000 mile advance notice and then it warns 20 times before it will refuse to start. Replacement fluid can be found at any MB dealer, but in normal use it gets replenished during routine service. So for now, I’m not carrying extra. I’ll post if towing makes the car require more AdBlue fills than are included in the routine service intervals.

  8. says

    Barry, I didn’t get the recall notice yet, but I should. The “fix” is just to apply some reflectors to comply with Federal regulations. I’ll probably get it done eventually, or add my own reflectors.

  9. Tim says

    Congratulations on your new tow vehicle. It is certainly an upgrade over your former vehicle.

    Sounds like you are going to be an unpaid towing test pilot for MB on this one, with all the hurdles you have already had to address..(it would have been boring to hook up a Dodge/Chevy/Ford diesel pickup and head down the highway 30 minutes later:-)

    Hopefully the drivetrain is up the tasks that are down the highway. All that said, you have a tow vehicle with serious bling.

  10. Jack Palmer says

    I have to say, it’s an odd choice of tow vechiles for someone promoting Airstream an American icon and Tour of America. First a Nissan and now a Mercedes? The combination has that New England snob appeal if nothing else. I consider myself pretty liberal, having grown up within blocks of John Hopkin University and graduating from The Maryland Institute of Art where there was every type of foreign car but if you’re promoting the pinical of American travel trailer design and build shouldn’t you be towing with American Iron?

  11. says

    You’re kidding, aren’t you Jack? Since when does owning an Airstream obligate someone to a particular make of tow vehicle?

  12. John says

    Witter and Westfalia make after-market hitches for the MB GL and ML ranges.

    I know, I have had one fitted (admittedly in Europe).
    They are not particularly difficult to fit, you could get one shipped over form Europe and fitted locally by your favourite spanner guy.


  13. says

    Hi John. Always great to hear from our European readers!

    I did learn about the Westfalia hitch, but unfortunately we can’t use the Euro-spec hitches here in the US. We need a different type of coupling (a 2″ square receiver) and modifying the European hitch to accommodate that would be more difficult than strengthening the US version hitch.

  14. Doug Pulling says

    Rich – What did your dealer do to get your
    GL signal acquisition module (SAM) to recognize the LED lights in your trailer? I have the identical problem with an ML, and the dealer has been supplying adapters for the cable, none of which have worked.

    Port Ludlow, WA

  15. says

    Hi Doug

    I used the adapter cable available from VW dealers, part #ZVW 808 004 (7 pin to 7-pin). Only some dealers stock it, so if your local dealer doesn’t have it, ask them to search other dealer inventory. You can also buy a similar cable made by Valley at http://www.etrailer.com/p-V39010.html

    The cable simply adds a resistor into the line to simulate the resistance of incandescent lights. We later eliminated the need for the cable by permanently wiring in a couple of incandescent lights. These reside in the wiring closet inside the trailer.

    Note that before this worked, we did have to reprogram the SAM at the dealer, even though the car came with the factory hitch. Ask your dealer for Technical Bulletin T-B-31.19/07d and make sure your car has the appropriate SAM installed, and the correct wiring.

  16. abe lincoln says

    I just picked up my GL 350 yesterday…. i got an 2009 from a dealer in Roanoke VA…

    34,000 miles one owner…. keyless, leather,

    For the first time in my life i got to tow with cruse control… (my 27 is only 6000#)

    the stinger from the 2005 suburban is too low …

    but i am taking my Airstream to Out of Doors mart for some serious battery adding..

    in 76 airstream only put in one…

  17. says

    Congratulations, Abe. You can get a replacement stinger free from Hensley (you pay shipping) — just call them to arrange the correct one. Mine is a straight stinger but a 2″ drop might work better for you.

    Be sure to have the OEM hitch reinforced, as the welds connecting the receiver box to the main tube are known to crack.